The question of which UI/UX issues should be considered as showstoppers when releasing a product to the market has always been of interest to me. I am curious to get some thoughts as to how would you classify UI/UX issues as minor, important, critical, and showstoppers when considering a product release.
According to Jakob Nielsen:
Another view by Paul J. Sherman takes into account business objectives when rating the severity of UX issues:
Also, this post by Jeff Sauro nicely summarizes some of the major scales for measuring the severity of usability issues in one table.
I think there are 2 types of products. The first one is a product that users really need but does not yet exist. In that case, users may complain about your design but you'll have time to improve it latter. Having said that, I still thing the it's important enough for the release.
The second type is a product that already exist. In that case UI/UX is critical because if a user feels uncomfortable with the UI he won't use your product, he will look for another product with a better UI.
Let's say that if your product is unique enough you might be able to release it with a "good" initial UI but if you think you'll have to works hard to get users choose your product over another an excellent UI will make your work much easier.